Somewhat relevant. [darwin](https://github.com/yglukhov/darwin) package is supposed to be a complete collection of macos/ios frameworks, which it is not at the moment, but new bindings can be easily declared like in this [NSView](https://github.com/yglukhov/darwin/blob/master/darwin/app_kit/nsview.nim). Advantage of this way (instead of nim's builtin `importobjc`) is that there's no header dependencies, the files can be compiled with either C or C++ backend, and objc compiler is not required.
Subclassing objc/swift in nim is not implemented yet, but eventually will be if there's enough interest.
